Stroke is common, costly and devastating. Stroke is the second most common cause of hospitalization among Medicare beneficiaries. It is also responsible for substantial mortality, morbidity and health care costs. There is a desperate need to improve stroke care. A central constraint to improving stroke care has been a lack of information on how to measure the quality of stroke care. Although several organizations have identified process measures as potential quality indicators, few data are available regarding whether the proposed measures actually impact stroke outcomes in clinical practices. We will investigate whether specific process measures are associated with better outcomes in a diverse, population-based national cohort. Our goal is to define measures that can be used to assess the quality of stroke care among patients hospitalized with acute ischemic stroke. This application proposes analyses based on the National Stroke Project database. The National Stroke Project was part of a Center for Medicare and Medicaid Study program looking at quality indicators for stroke care, by state, among Medicare beneficiaries. Our primary aim is to determine whether specific processes of stroke care are associated with better outcomes among patients hospitalized with acute ischemic stroke. We hypothesize that variations in the use of specific processes of care will be associated with differences in hospital outcome (in-hospital mortality or discharge to nursing home). The Secondary aim is to explore if, among processes of care associated with better stroke outcomes, the associations are independent of patient and structural characteristics. Our application is ideally suited to PA-01-040 (AHRQ Small Research Grant Program). The RO3 Award will permit new analyses of the National Stroke Project database. The aims and proposed analyses of this application go beyond the analyses proposed, and funding available for, the National Stroke Project. The aims of this research project are designed to complement and extend, the original National Stroke Project goals by generating new knowledge that will be instrumental in accelerating efforts to validate quality measures, initiatives to improve care, and will help inform new health services research efforts for the large and growing population of Americans with cerebrovascular disease.